Scaffold Python project with pyproject.toml and pytest

Add a src/-layout package (shard_wiki), hatchling build config, pytest
and ruff configuration, and smoke tests proving the import path and test
harness are wired correctly. Update CLAUDE.md with real build/test commands.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/shard_wiki/__init__.py

@@ -0,0 +1,10 @@
+"""shard-wiki — Git-based Markdown wiki orchestrator and federation layer.
+
+See INTENT.md for the authoritative specification of scope and boundaries.
+This package orchestrates wiki-shaped content across heterogeneous *shards*;
+it is not itself a wiki engine.
+"""
+
+__version__ = "0.0.0"
+
+__all__ = ["__version__"]